The Lower Keys begin at the end of the Seven Mile Bridge and include Little Duck Key, Big Pine Key, the Torch Keys, Bahia Honda Key, Cudjoe Key, Sugarloaf Key, Summerland Key, the Saddlebunch Keys, Big Coppitt Key, Stock Island, and Key West. Highlights of the Lower Keys [Fig. 7] include some of the finest beaches in the world, great diving and fishing opportunities and a chance to see wild miniature deer. (For more information on the natural and human history of the Keys, see the introduction to the Upper Florida Keys.)
The Lower Keys were sparsely settled in the mid-1800s. The few who stayed in this isolated land made their living from making charcoal, fishing, farming, and sponging. By comparison, Key West at that time had 18,000 residents and was the largest city in Florida.
When Flagler's railroad came through in 1912, the isolation was over and for the next 23 years, trains ran daily through the lower Keys on the way to and from Key West. When the railroad was destroyed in 1935, the Overseas Highway kept the link open. Even today, however, the Lower Keys population, minus that of Key West, is around 16,500. The population of Key West is about 25,000.
One interesting sight you'll pass is the Flagler Bridge off the southern peninsula of Bahia Honda at MM 36. From the highway, look over at the top of the old trestle-type railroad bridge to the south. When the Overseas Highway was constructed, the railbed of the bridge wasn't wide enough for a highway, so the designers reinforced the superstructure and ran the road right across the top, high over the railroad track.